p r a t t



E. LJPRANTT. STEAM BOILER CLEANER.

Patented July 2,1867.

gnifrh gtstrewfiatmt E. LQ-PR TT, OF B osr 0 N], MASSACHUSETTS.

i I Letters Patent No. 166,387, dated July 2, 1867.

IMPROYBMENT IN BOILER-TUBE as Ens.

TO ALL n ne)! 11'; MAY coNcnnN;

Be it known that I, L; PRATT, of Boston, in the'coun'ty of Sufi'olkfandState of Massachusetts, have invented an' improved Boiler-Tube Scraper;and I do hereby declare that the following, taken in connection with thedrawings which accompany and form part of this specification, is adescription of my invention s uflicient to enable those skilled in theartto practise it.

' The invention relates to the constriiction of a scraper for cleaningthe tubes of steam boilers, and consists primarily in an arrangement ofa series of segmental or sectional scraping-blades around a'centralrodor spindle made movable longitudinally within the scrapers, \\hich areso arranged with relation to a tube-or sleeve through which the ,rodpasses, and with relation to cxpanding shanlis' byuhich they areconnected with and hung to a head attached to the sleeve, and toanenlargement formed on the rod,' that while they may be introduced intothe tnbe in a contracted or closed form to any depthpermittedbythelength of the sleeve, theymay be expanded so as to bring their scrapingcdgesagainst;thesides of th e tube to be cleaned; bydriving. the rodinwards by a blow or pressure upon the head thereof, and-in thisexpandedposition maybe drawn from the 3 tube, orreciprocatcd within it, bylongitudinal lnoi etnent'of th e-- s1cc i',e, in' such manneras to.scrape all alldeposits'upon the surfac'e of said tube. The shanksat;,tire-endsat which {thescrapers are fixed or formed are jointed tothe head so as to permit a slight rocking motion'imcach scraping edge,and cach-is cushioned upon 7 V as pring uhich bears thc' sc rapersagainst the surface of the tube, \ihen theyflareex panded, but allowsthem to ."yieldso'm'eirhat to resisting inequalitiesinobstructionsjnponfthc surface being scraped. y 1 The dra vingsrepresent a scraper embodying my inventioinffA shows aside view of theseme /the scraping fedgcsfbeing closed together. I}, acentralsectioinsaidjetlges binglexpandem C, a cross-section through the"pins, by which the scrapers are connected to the head. Il a:cross-section taken on the line :v. a denotes a headQha ving" slots b onits side s, in.uhich are pivoted,fon.pins c, shanks it, having fixedupon or preferably formed,integraluritlitheir-frec ends,-segmentalbladesio ls cl'ape rsQi2, the enter edge of each of which is formedwitha cunve concentric, orapproximately concentric, with t-he innersurfacejof the tube to be cleaned. The head dis scre ii'ed orlothern'isefastened upon thcendof as-leve, f, through which extends a rod, g, uponthe end of uhichtniay befixed asap, IL, and-this rodhas nponl 'it-sng;enlargement or expander, ll, as seen at B. Each shank piece d hassccuredto-itslinner face a long-spring,ltfbending inwardly toward the axis ofthe rod vg, andirhen tbe bladese arc; contracted or closed"together,1;thc spfingscome up to or nearly into contact with the rod,with the ex-pander i drawn just within these bonds, as seen at .A. lnthis condition the blades are introduced into a tnbe, l, to be cleaned,and are carried to the rear end thereof, the sleeve f being made ofrequisite length for that pnrpose.' When bionght to the pointixt whichthe scraping lsto commence, the rod g is forced inwardly, driving "theexpander 2' against the springaandforcing thesprings outwardly, therebyexpanding the blade e and forcing their scraping'edges againsttheinnensurface of the tube, "the cap it arrestingthc inward movement ofthe rod, so as to leave the expaiider 1' against the bends in thesprings. If the sleeve f be now drawn from the tube, it willbe'obviousthat the blades 0 will draw with them the accumulations ofsoot, &c., deposited on the inner surface of the ,tube, cushionin'gtheblades by means of the springs, enabling them to yield to the natural orpermanent inequalities in the surface of the tube; The shanks d may havesprings formed integral withthem, or may have/their innersurfaces-formed with inclines to be acted upon by the enlargement on therod bnt cushioning the shanksupon the springs, as shown, is 'consideredpreferable.

It is desirable that each blade should be capable of a slight rockingmovement in the line of its edge, for which purposeeach pivot hole, m,is first made of size to correspond-withthe'diameter of the pin a, andthe hole is then reamed out at each side towards the centre, as seen atC, thereby enabling the shank, and-through it the dge of the blade, torock as may be necessary to cause it tomcat the surface of" the tube,the slot '6 being of enough greater width than the'thickness of theshank to permit such rocking movement. Each shank with its blade ispreferably made of malleable cast'iron, formingthe two in one piece ofmetal, rendering the blade much more enduring than if it were fastenedupon theshank. Each blade has one part, n, below the otheri part, a, toallow the part'o of the next adjacent blade to shut in under it when theblades are closed together.

Scrapers made, ,as shown and described, are found "very eflicient inremoving carbondeposits from boilertubes, and are greatly superior tobrushes and other devices heretofore 'used forsucll purpose, ivhile theinstrument is inexpensive as well as enduring, and is very easilymanipulated.

When necessary or desirable to contract the blades while they areexpanded within the tube, the rod is drawn outwardly, causing theexpander to strike the inner ends of the shanks, and thereby to drawtogether the blades, as will b: readily understood. I v

I claim, in combination with a series of scraping-blades arranged asdescribed, a sliding-rod, by movement of which the scraping edges may beexpanded or contracted when they arewit-llin a tube, substantially asdescribed.

Also, in combination with the blades and their shanks and the movablerod, the springs upon which the shanks are cushioned when the blades areexpanded, substantially as set forth.

E; L; PRATT.

Witnesses.

F. GOULD, S. B. Kmmm.

